The Influence Of G-CSF And Thy1.1 Stem Cells On Nointimal Formation Of Injured Artery

Objective (1) To look for a convenient, quick method of making rat carotid arterial injury model with PTCA balloon, and to investigate the character of intimal thickening by pathology; (2) To compare the effect of low-molecular-weight heparin(LMWH) and unfractionated heparin(UFH) in the process of making rat carotid arterial injury model with Medtronic balloon; (3) To explore the influence of G-CSF on the injured carotid artery ; (4) To evaluate the effect of different treatment of G-CSF on endothelial hyperplasia after saccule injury of rat common carotid artery and the effect on injured blood vessel; (5) To study the effect of Thy-1.1+ stem cells transplant on neointimal, and evaluate the influence of stem cells transplant on restenosis; (6) To study whether recombination G-CSF can cooperate with Thy-1.1+ stem cells to repair the injured artery.Methods The study included three stages. First: 60 female SD rats were equally divided into 2 groups: LMWH group and UFH group, to compare the effect of LMWH and UFH in the process of making carotid arterial injury model. Second: Another 90 female SD rats were randomly divided into 3 groups (30 each group), namely G-CSF pretreated group, G-CSF posttreated group and control group. The G-CSF pretreated group rats were injected daily with 30μg G-CSF /kg for 7 days before carotid artery injury, the G-CSF posttreated group rats were injected daily with 30μg G-CSF /kg for 7 days shortly after carotid artery injury, and the control group was merely underwent carotid artery injury. The animals were killed shortly after injury and 3, 7, 14, 21, 28 days after balloon denudation, and the samples of carotid artery were harvested for pathology and RT-PCR for eNOS mRNA, to evaluate the effect of different treatment of G-CSF on endothelial hyperplasia. Third: 30 male 4-6w old SD rats were killed for Thy-1.1+ stem cells. Another 90 female SD rats were randomized divided into stem cells transplant group, combination transplant group and control group with 30 rats in every group. The stem cells transplant group rats were injected about 5x106 Thy-1.1+ stem cells into the injured artery after carotid artery injury; the combination transplant group rats were injected daily with 30μg G-CSF /kg for 7 days before carotid artery injury and were injected about 5x106 Thy-1.1+ stem cells into the injured artery shortly after the artery injury, and the control group was underwent carotid artery injury and injected the same amount of saline. The animals were killed shortly after injury and 3, 7, 14, 21, 28 days after balloon denudation, and the samples of carotid artery were harvested for pathology, RT-PCR and in situ hybridzation(ISH) to detect the transplanted cells in the injured artery.Results (1) Irregular intimal thickening and stenosis of arterial cavity were observed since 1 week after balloon denudation. At 2 to 4 week, the intimal thickening reached peak. More rats in LMWH group accomplished carotid arterial injury model than UFH group, and the thrombosis is more frequently in UFH group. (2) It was found that the intimal thickness was thinner in G-CSF pretreated group, and eNOS mRNA expression was higher in G-CSF pretreated Group compared with that in control Group(P <0.05), I/M ratio was the smallest in G-CSF pretreated Group. (3) ISH can trace the transplanted cells in the rats of the stem cells transplant group and combination stem cells transplant group. (4) The intimal thickness was thinner in stem cells transplant group and combination stem cells transplant group, and eNOS mRNA expression was much higher compared with those in control group. I/M ratio was lower in combination stem cells transplant group compared with that in stem cells transplant group. (5) The intimal thickness was lower in combination stem cells transplant group compared with that in G-CSF pretreated Group, and eNOS mRNA expression was higher in combination stem cells transplant group.Conclusions (1) LMWH is more effective in the process of making carotid arterial injury model than UFH. (2) G-CSF pretreatment accelerated reendothelialization and decreased neointimal formation following vascular injury, which suggest that exogenous G-CSF may be a feasible treatment to prevent restenosis after PCI. The pretreatment G-CSF is more effective than posttreatment G-CSF.(3)Thy-1.1+ stem cells transplant can promote the repairing of the injured artery. (4) G-CSF combined with Thy-1.1+ stem cells transplant can accelerate reendothelialization and decrease neointimal formation following vascular injury, G-CSF can cooperate with Thy-1.1+ stem cells to repair the injured artery. (5) The repairing of G-CSF and Thy-1.1+ is associated with upregulation of eNOSmRNA expression.